Abstract: A ram air turbine rotor comprises at least one intra-flow path shroud structure coupled between rotor blades, along a radial position between a support disc and an outer rim. The shroud structure includes shroud sectors each coupled between a respective pair of blades. The sectors each include a first edge adjacent to leading edges of the respective pair of blades, the first edge including a first curved segment, and a second edge adjacent to trailing edges of the respective pair of blades, the second edge including a second curved segment. The curved segments are each partially defined by a respective ellipse having a semi-major axis and a semi-minor axis. The semi-major axis is a portion of a spanwise distance between the respective pair of blades. The semi-minor axis is a portion of an axial distance between the leading edge of one blade and the trailing edge of an adjacent blade.

Abstract: A ram air turbine rotor comprises at least one intra-flow path shroud structure coupled between rotor blades, along a radial position between a support disc and an outer rim. The shroud structure includes shroud sectors each coupled between a respective pair of blades. The sectors each include a first edge adjacent to leading edges of the respective pair of blades, the first edge including a first curved segment, and a second edge adjacent to trailing edges of the respective pair of blades, the second edge including a second curved segment. The curved segments are each partially defined by a respective ellipse having a semi-major axis and a semi-minor axis. The semi-major axis is a portion of a spanwise distance between the respective pair of blades. The semi-minor axis is a portion of an axial distance between the leading edge of one blade and the trailing edge of an adjacent blade.

Abstract: A ram air turbine rotor comprises at least one intra-flow path shroud structure coupled between rotor blades, along a radial position between a support disc and an outer rim. The shroud structure includes shroud sectors each coupled between a respective pair of blades. The sectors each include a first edge adjacent to leading edges of the respective pair of blades, the first edge including a first curved segment, and a second edge adjacent to trailing edges of the respective pair of blades, the second edge including a second curved segment. The curved segments are each partially defined by a respective ellipse having a semi-major axis and a semi-minor axis. The semi-major axis is a portion of a spanwise distance between the respective pair of blades. The semi-minor axis is a portion of an axial distance between the leading edge of one blade and the trailing edge of an adjacent blade.

Abstract: A ram air turbine rotor comprises at least one intra-flow path shroud structure coupled between rotor blades, along a radial position between a support disc and an outer rim. The shroud structure includes shroud sectors each coupled between a respective pair of blades. The sectors each include a first edge adjacent to leading edges of the respective pair of blades, the first edge including a first curved segment, and a second edge adjacent to trailing edges of the respective pair of blades, the second edge including a second curved segment. The curved segments are each partially defined by a respective ellipse having a semi-major axis and a semi-minor axis. The semi-major axis is a portion of a spanwise distance between the respective pair of blades. The semi-minor axis is a portion of an axial distance between the leading edge of one blade and the trailing edge of an adjacent blade.

Abstract: A method of manufacturing a multistage axial-centrifugal compressor for a gas turbine engine and a multistage axial-centrifugal compressor that includes a series of axial compressor stages each having a rotor mounted to a common shaft positioned upstream from a centrifugal compressor stage mounted to the common shaft. The method includes determining an operational rotor tip speed for each of the axial stages. The method includes comparing the operational rotor tip speed to a threshold range value and determining to machine an airfoil of the rotor for at least one of the axial stages by an arbitrary manufacturing approach based on the operational rotor tip speed as greater than the threshold range value. The method includes determining to machine an airfoil of the rotor for at least one of the axial stages by a flank manufacturing approach based on the operational rotor tip speed as less than the threshold range value.

Abstract: Variable vane devices containing rotationally-driven translating vane structures are provided, as are methods for fabricating variable vane devices. In one embodiment, the variable vane device includes a flow assembly having a centerline, an annular flow passage extending through the flow assembly, cam mechanisms, and rotationally-driven translating vane structures coupled to the flow assembly and rotatable relative thereto. The translating vane structures include vane bodies positioned within the annular flow passage and angularly spaced about the centerline. During operation of the variable vane device, the cam mechanisms adjust translational positions of the vane bodies within the annular flow passage in conjunction with rotation of the translating vane structures relative to the flow assembly.

Abstract: A method of manufacturing a multistage axial-centrifugal compressor for a gas turbine engine and a multistage axial-centrifugal compressor that includes a series of axial compressor stages each having a rotor mounted to a common shaft positioned upstream from a centrifugal compressor stage mounted to the common shaft. The method includes determining an operational rotor tip speed for each of the axial stages. The method includes comparing the operational rotor tip speed to a threshold range value and determining to machine an airfoil of the rotor for at least one of the axial stages by an arbitrary manufacturing approach based on the operational rotor tip speed as greater than the threshold range value. The method includes determining to machine an airfoil of the rotor for at least one of the axial stages by a flank manufacturing approach based on the operational rotor tip speed as less than the threshold range value.

Abstract: Variable stator vane assemblies and stator vanes thereof having a local swept leading edge are provided. The variable stator vane comprises an airfoil disposed between spaced apart inner and outer buttons centered about a rotational axis. The inner and outer buttons each having a button forward edge portion and the airfoil including leading and trailing edges, pressure and suction sides, and a root and a tip. The leading edge, at least a portion of which extends forward of the buttons, includes a local aft sweep at the tip, thereby forming a locally swept tip of the leading edge thereat. The button forward edge portion of the outer button is substantially vertically aligned with the locally swept tip of the leading edge. Methods are also provided for minimizing endwall leakage in the variable stator vane assembly using the same.

Abstract: A rotor blade comprises a mount and a blade that extends from the mount along a radial axis. The leading edge includes an indent segment. The leading edge has a leading edge radial length measured along the radial axis. The indent segment has an indent radial length measured along the radial axis. The indent segment has an indent depth. A first ratio of the indent radial length to the leading edge radial length is at most 0.5. A second ratio of the indent depth to the indent radial length is at least 0.05.

Abstract: Variable vane devices containing rotationally-driven translating vane structures are provided, as are methods for fabricating variable vane devices. In one embodiment, the variable vane device includes a flow assembly having a centerline, an annular flow passage extending through the flow assembly, cam mechanisms, and rotationally-driven translating vane structures coupled to the flow assembly and rotatable relative thereto. The translating vane structures include vane bodies positioned within the annular flow passage and angularly spaced about the centerline. During operation of the variable vane device, the cam mechanisms adjust translational positions of the vane bodies within the annular flow passage in conjunction with rotation of the translating vane structures relative to the flow assembly.

Abstract: Variable stator vane assemblies and stator vanes thereof having a local swept leading edge are provided. The variable stator vane comprises an airfoil disposed between spaced apart inner and outer buttons centered about a rotational axis. The inner and outer buttons each have a button forward edge portion. The airfoil includes leading and trailing edges, pressure and suction sides, and a root and a tip. The leading edge, at least a portion of which extends forward of the buttons, includes a local forward sweep at the root, thereby forming a locally swept root of the leading edge thereat. The button forward edge portion of the inner button is substantially vertically aligned with the locally swept leading edge root. Methods are also provided for minimizing endwall leakage in the variable stator vane assembly using the same.

Abstract: Variable vane devices containing rotationally-driven translating vane structures are provided, as are methods for fabricating variable vane devices. In one embodiment, the variable vane device includes a flow assembly having a centerline, an annular flow passage extending through the flow assembly, cam mechanisms, and rotationally-driven translating vane structures coupled to the flow assembly and rotatable relative thereto. The translating vane structures include vane bodies positioned within the annular flow passage and angularly spaced about the centerline. During operation of the variable vane device, the cam mechanisms adjust translational positions of the vane bodies within the annular flow passage in conjunction with rotation of the translating vane structures relative to the flow assembly.

Abstract: A field deployable, portable structured light measurement (SLM) apparatus, together with a structured light measurement process to manage part to part variation in production and in the field, to support both rotor airfoil mistuning and rotor airfoil repair limits.

Abstract: A rotor blade comprises a mount and a blade that extends from the mount along a radial axis. The leading edge includes an indent segment. The leading edge has a leading edge radial length measured along the radial axis. The indent segment has an indent radial length measured along the radial axis. The indent segment has an indent depth. A first ratio of the indent radial length to the leading edge radial length is at most 0.5. A second ratio of the indent depth to the indent radial length is at least 0.05.

Abstract: Variable vane devices containing rotationally-driven translating vane structures are provided, as are methods for fabricating variable vane devices. In one embodiment, the variable vane device includes a flow assembly having a centerline, an annular flow passage extending through the flow assembly, cam mechanisms, and rotationally-driven translating vane structures coupled to the flow assembly and rotatable relative thereto. The translating vane structures include vane bodies positioned within the annular flow passage and angularly spaced about the centerline. During operation of the variable vane device, the cam mechanisms adjust translational positions of the vane bodies within the annular flow passage in conjunction with rotation of the translating vane structures relative to the flow assembly.

Abstract: Embodiments of a forward-swept impeller are provide, as are embodiments of a gas turbine engine containing a forward-swept impeller. In one embodiment, the gas turbine engine includes a shaft and a forward-swept impeller mounted to the shaft. The forward-swept impeller includes, in turn, an inboard impeller section, an outboard impeller section circumscribing the inboard impeller section, and a plurality of hub flow paths extending over the forward-swept impeller from the inboard impeller section to the outboard impeller section. The plurality of hub flow paths each have a flow path exit that is tilted in a forward direction, as taken along a line tangent to the flow path exit.

Abstract: Variable stator vane assemblies and stator vanes thereof having a local swept leading edge are provided. The variable stator vane comprises an airfoil disposed between spaced apart inner and outer buttons centered about a rotational axis. The inner and outer buttons each have a button forward edge portion. The airfoil includes leading and trailing edges, pressure and suction sides, and a root and a tip. The leading edge, at least a portion of which extends forward of the buttons, includes a local forward sweep at the root, thereby forming a locally swept root of the leading edge thereat. The button forward edge portion of the inner button is substantially vertically aligned with the locally swept leading edge root. Methods are also provided for minimizing endwall leakage in the variable stator vane assembly using the same.

Abstract: Variable stator vane assemblies and stator vanes thereof having a local swept leading edge are provided. The variable stator vane comprises an airfoil disposed between spaced apart inner and outer buttons centered about a rotational axis. The inner and outer buttons each have a button forward edge portion. The airfoil includes leading and trailing edges, pressure and suction sides, and a root and a tip. The leading edge includes a local forward sweep at the root, a local aft sweep at the tip, or both, thereby forming a locally swept leading edge thereat. The button forward edge portion of one or both of the inner and outer buttons is substantially coextensive with the locally swept leading edge. Methods are also provided for minimizing endwall leakage in the variable stator vane assembly using the same.

Abstract: A field deployable, portable structured light measurement (SLM) apparatus, together with a structured light measurement process to manage part to part variation in production and in the field, to support both rotor airfoil mistuning and rotor airfoil repair limits.

Abstract: Embodiments of a forward-swept impeller are provide, as are embodiments of a gas turbine engine containing a forward-swept impeller. In one embodiment, the gas turbine engine includes a shaft and a forward-swept impeller mounted to the shaft. The forward-swept impeller includes, in turn, an inboard impeller section, an outboard impeller section circumscribing the inboard impeller section, and a plurality of hub flow paths extending over the forward-swept impeller from the inboard impeller section to the outboard impeller section. The plurality of hub flow paths each have a flow path exit that is tilted in a forward direction, as taken along a line tangent to the flow path exit.